Invertebrates from the Low Head Member (Polonez Cove Formation, Oligocene) at Vauréal Peak, King George Island, West Antarctica
Invertebrates from the Low Head Member (Polonez Cove Formation, Oligocene) at Vauréal Peak, King George Island, West Antarctica
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来自西南极洲乔治王岛 Vauréal 峰低头层（渐新世波罗涅斯湾组）的无脊椎动物
DOI：
10.1017/s0954102007000867
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发表时间：
2008
影响因子：
1.6
通讯作者：
A. Rocha
中科院分区：
文献类型：
--
作者：
Fernanda Quaglio;L. Anelli;P. R. Santos;J. A. J. Perinotto;A. Rocha
本文描述了西南极乔治王岛Vaureal峰地区Polonez Cove组（最新的早渐新世）低头段的8个海洋无脊椎动物分类群，包括2个双壳类新种。化石组合包括腕足类（Neothyris sp.和Liothyrella sp.）的代表，双壳类（Adamussium auristriatum sp. nov.，? Adamussium cf. A. alanbeui Jonkers和Limatula（tolima）ferraziana sp. nov.），苔藓虫，多毛类（蛇管）和棘皮动物。标本出现在泥石流沉积物的低头成员，作为一个高能量，浅海环境中的扇三角洲设置的一部分。Liothyrella sp.，Adamussium auristriatum sp. nov.和Limatula ferraziana sp. nov.是乔治王岛上这些属的最古老的记录之一。尽管它们的数量有限和多样化，本研究的双壳类和腕足类显示出一种整体的分散模式，大致适合在南极洲周围的洋流的顺时针循环完成的两个步骤。第一次是在始新世/渐新世边界的塔斯马尼亚门户开放之后，沿着南极洲东缘，第二次发生在后古近纪时期，在南极半岛和南美洲之间的德雷克通道开放之后，沿着南极洲西缘。
Abstract Eight taxa of marine invertebrates, including two new bivalve species, are described from the Low Head Member of the Polonez Cove Formation (latest early Oligocene) cropping out in the Vauréal Peak area, King George Island, West Antarctica. The fossil assemblage includes representatives of Brachiopoda (genera Neothyris sp. and Liothyrella sp.), Bivalvia (Adamussium auristriatum sp. nov., ?Adamussium cf. A. alanbeui Jonkers, and Limatula (Antarctolima) ferraziana sp. nov.), Bryozoa, Polychaeta (serpulid tubes) and Echinodermata. Specimens occur in debris flows deposits of the Low Head Member, as part of a fan delta setting in a high energy, shallow marine environment. Liothyrella sp., Adamussium auristriatum sp. nov. and Limatula ferraziana sp. nov. are among the oldest records for these genera in King George Island. In spite of their restrict number and diversification, bivalves and brachiopods from this study display an overall dispersal pattern that roughly fits in the clockwise circulation of marine currents around Antarctica accomplished in two steps. The first followed the opening of the Tasmanian Gateway at the Eocene/Oligocene boundary, along the eastern margin of Antarctica, and the second took place in post-Palaeogene time, following the Drake Passage opening between Antarctic Peninsula and South America, along the western margin of Antarctica.